Expression mechanism for automatic musical instruments



C. F. STODDARD.

EXPRESSION MECHANISM FOR AUTOMATIC MUSICAL INSTRUMENTS. APPLICATION FILED MAY 25, I914.

1,409,485. Patented Mar- 14, 1922.

UNITED STATES PATENT OFFICE.

CHARLES F. STODIDARD, OF NEW "YORK, N. Y., ASSIGNOR TO AMERICAN PIANO COMPANY, NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

EXPRESSION MECHANISM FOR AUTOMATIC MUSICAL INSTRUMENTS.

To all whom it may concern:

Be it known that'I, CHARLES F. STODDARD, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented an Improvement in Expression Mechanism for Automatic Musical Instruments, of which the following description, inconnection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to apparatus for automatically varying playing intensities in automatic musical instruments, such, for instance, as playerpianos and the like.

Among other objects, the invention is intended to provide apparatus capable of pro ducing prompt changes in playing intensity while maintaining intensitiesso far as may be desired, regardless ofthe number of tones sounded.

The character ofthe invention may be readily understood by reference to the accompanying drawing, which shows diagrammatically one illustrative embodiment.

'In the drawings, bellows 1 exemplifies a source of power for operating the striker pneumatics 2 which may be operated selectively, as well understood by those skilled in the art, fro1n a tracker board through ducts 3. A passage 1 connects the source of power '1 with the action chest 5 of the player actions." A va'lve 6 controls the passage 4 to regulate and vary the extent to which the pressure at the action chest 5 is subjected to the high tension or exhaust at the source 1. In other words, the valve6 regulates and varies the flow of air from the action chest to the source 1.

A regulator bellows 7 is connected by a port;8 with the passage 4, and said regulator bellows 7 is connected by an arm 9 with the valve 6; A' spring 10 is connected to the movable-board of the regulator bellows 7 and connects said movable board with the movable board of an expression bellows 11. \Vhen the expression bellows 11 is collapsed, the tension of the spring 10 is thereby in creased, so as tomodify the action of the regulator 7, with the result that the opening by the valve 6 is inorea sed'and the playing by the actions 2 is rendered louder, all as will be readily. understood by those-skilled in the art. a

Specification of Letters Patent.

Patented Mar. 14, 1922.

. Application filed May 25, 1914. Serial No. 840,868.

In the illustrative embodiment, the expression bellows 11 may be collapsed or expanded fully or partially at a high speed, in order to produce substantially instantaneous steps of change of playing intensity; or bellows 11 may be collapsed or expanded gradually at a relatively moderate speed, in order to produce gradual changes in playing intensity for crescendos or diminuendos. To suit thesepurposes the bellows 11 may be exhausted rapidly through a duct 12 of comparatively large capacity suflicient to collapse the bellows substantially instantaneously. When exhausted through said duct 12, the bellows 11 may be wholly collapsed, so as practically instantaneously to increase the tension of the spring 10 to its maximum, and thereby produce fortissimo playing, or the total high speed collapse of the bellows 11 may be prevented, so as to tension the spring 10 to an extent less than the maximum. For instance, an auxiliary stop bellows 13 may be provided having mounted upon its movable board a stop piece 14 to be interposed in the path of a stop piece 15 on the movable board of the expression bellows 11. The auxiliary stop bellows 13 may be exhausted and thereby collapsed through a duct 16. \Vhen the stop bellows 13 is collapsed, the stop 14: is thereby interposed in the path of the stop 15 of the expression bellows 11, preferably at some point intermediate the wholly expanded position and the wholly collapsed position of the bellows 11, for instance, midwa Y between these positions.

V ith this arrangement, if the stop bellows 13 be collapsed, and the expression bellows 11 be then exhausted through the duct 12, said bellows 11 will be then practically instantaneously collapsed through substantially half of its maximum extent of collapse, thereby tensioning the spring 10 tocause forte playing.

In the stationary board of the expression pneumatic 11 is provided a port 17 of sutficient area to admit atmosphere rapidly, and thereby permit a quick and practically instantaneous expansion of the pneumatic. The port 17 is controlled by a valve 18 connected to the movable board of a pneumatic 19 which may be exhausted through a duct 20. The expression pneumatic 11, having been wholly or partly collapsed as described,

may be rapidly expanded to reduce the playing intensities by exhausting the pneumatic 19 through 'the duct 20, and thereby opening the ports 17 to admit atmosphere.

The expression pneumatic 11 may be exhausted through a duct 21 having small capacity as compared with that of the duct 12. Thus, through the duct 21, the pneumatic 11 will be more slowly exhausted, so that it would be collapsed slowly to increase gradually the tension of thespring 10 to give the effect of a crescendo. To produce a corresponding diminuendo, atmosphere may be admitted to the ex ression bellows 11 through the comparatively restricted duct 21.

Any suitable automatic means, preferably controlled by vents in the tracker, may be emplo ed to overn the various ducts 12, 16, 20 ant 21. or instance, the so-called automatic actions described in patent No. 1,008,291, dated November 7, 1 911, to Welte & Bockisch may be employed for this purpose. The accompanying drawings show certain parts of'the automatic act-ions described in the above mentioned patent, and reference may be made thereto for a detailed description of the valve mechanisms herein shown. A wind trunk 50 communicates with the'wind trunk 4 through a duct 51 opening to wind trunk 4 between the regulator valve 6 and the source of exhaust. A series of diaphragm chambers 52-57 are located below the wind trunk 50, are provided with suitable diaphragms and above these diaphragm chambers are corresponding valve chambers 5863 in which are mounted duplex valvesl Each of these chambers58-63 has a port openin to the high exhaust chest 50, and to atmosp iere through a passage 64 Each of the duplex valves mounted in said chambers is connected by a suitable valve stem with its corresponiling diaphragm. The duct 12 opening to the expression bellows 11 leads to valve chamber 58, duct 21 leads to valve chamber 60, duct 20 leads to valve chamber59, and duct 16 from bellows 13 leads to valve chamber 62. Above valve chambers 58, v60 and 62 are mounted diaphragm, chambers 65.-67, each provided with a suitable diaphragm connected respectively to the valves of chambers 58, 60 and 62. Ducts 75, 77'and 79 lead respectively from valve chambers 58, 60 and 62 to the upper sides of the diaphragms in chambers 65, 66 and 67, while ducts 76, 78 and 90 lead respectively from valve chambers 59, .61 and 63 to the underside of said diaphragms, for purposes latter described. Tracker ducts 687 3 lead from corresponding vents in a tracker board 7-1 to the diaphragm chambers 52-757 respectively.

The automatic operation of the valve mechanism may be accomplished by means of perforations near the edge of the note sheet. This operation is fully explained in the above mentioned patent, and reference may be had thereto for a full description of said operation. Briefly, however, the opening of vent 68 raises the valve in chamber 58 and connects duct 12 with high exhaust thereby quickly exhausting the expression bellows 11. Thus raising the valve in chamber 58 places diaphragm chamber 65 in communication with high exhaust through duct 75 and thus the closing of tracker vent 68 will have no effect to lower the valve in chamber 58. If, thereafter, tracker vent 69 is opened the valve in chamber 59 will place duct 20 in communication with exhaust, thus collapsing bellows 19 and admitting atmosphere to expression bellows 11, and also, through duct 76, admitting exhaust to the underside of the diaphragm in chamber 65 thus closin the port from chamber 58 to exhaust by ropping the valve. The opening of tracker vent 7 0 will raise the valve in valve chamber 60 and inaugurate a crescendo by exhausting the expression bellows 11 slowly through duct 21. This operation will continue regardless of the closing of tracker vent 70 until tracker vent 71 is opened to cancel the crescendo operation by raising the valve in chamber 61 and admitting exhaust to the underside of diaphagm 66 through duct 78. The opening of tracker vent 72 raises the valve in chamber 62 and thereby exhausts bellows 13. The bellows 13 will remain exhausted regardless of the closing of tracker vent 7 2 until vent 73 is opened to cancel the effect of the o ning of vent 72 as in the case of vent 68. T ese automatic actions in themselves form no part of this invention, and therefore they need not be described nor shown herein.

It will be observed that the valve 6 is always under the control of opposing forces, one force being the difi'erenential between atmospheric pressure and the low pressure of rarefied air in the passage 4, that differential acting upon the movable part of the regulator bellows 7 and tending to collapse the same to close the valve. The opposing force is that of the spring 10 actin upon the movable board of the regulator% and tending to open the valve 6. Normally when the expression pneumatic 11 is idle, these opposed forces seek a relation of balance, and thereby maintain uniform the pressure in the action chest 5 regardless of the-number of individual playing actions which may be -op erated together. The operation of the expression bellows 11 merely increases one of the opposed forces governing the valve 6,- i. e. the force exerted by the spring 10,--and thereby. modifies the regulation or maintaining action of the bellows 7 by increasing the force of the spring which requires to be balanced by the difi'erential between atmospheric pressure and the pressure within the bellows 7. The yielding character of the spring 10 permits the balance of force referredfto to be varied by the operation of the expression bellows 11, while also permitting the regulating action of the bellows 7 to continue unimpaired under the conditions of anew balancing relation established by the increasing tension of the spring 10.

It willbe noted that the valve 6 is always operated by the regulator bellows 7 and is only indirectly ailectedby the operation of the expression bellows 11, which first modifies the action of the regulator and therethrough indirectly produces aresultant efiect upon the valve 6.

It is to be understood that the invention is not limited to the particular construction. organization and mode of operation herein shown and described. On the contrary, the invention may be variously embodied and the illustrative construction may be variously modified within the scope of the sub-joined claims.

Claims- 1. In a musical instrument, the combination 01 player pneumatics; a source of power for actuating the player pneumatics; a tracker; automatic expression controlling means constructed and arranged to control the degree of pressure at the player pneumatics according as said expression controlling means are set, for high, low or intermediate pressures; means connecting the tracker and said automatic expression controlling means for governing the latter by the former; pressure-maintaining means including a spring for maintaining substantial uniformity of that pressure for which the said expression controlling means may at any time be set, whatever number of player pneuinatics be simultaneously operated; said expression controlling means being connected by said spring to said maintaining means, to transmit the action of the former to the latter.

2. In a musical instrument, pneumatic playing actions; a main bellows, a regulating bellows communicating with said main bellows and the playing actions; a valve between said main and said regulating bellows; means connecting the valve and regulating bellows; and expression bellows connected to the regulating bellows for modifying the action thereof, and thereby changing i11- tensities; and a movable stop device for said expression bellows to vary the extent of operation thereof.

In a musical instrument, pneumatic playing actions; a main bellows; a regulating bellows communicating with said main bellows and the playing actions: a valve between said main and said regulating bellows; means connecting the valve and regulating bellows; and expression bellows connected to the regulating bellows for modifying the action thereof, and thereby changing the playing intensities; and a stop device for said expression bellows, said stop device comprising a bellows arranged contiguous to the expression bellows and having a stop to limit movement of the movable board of said expression bellows.

4;. In a musical instrument, pneumatic playing actions; a main bellows; a regulating bellows communicating with the main bellows and playing actions; a regulating device between said main and regulating bellows; means for connecting the regulating device to the regulating bellows; an expression bellows connected to the regulating bellows for modifying the action thereof, and thereby changing playing intensities; and a stop device for said expression bellows; said stop device comprising an automatically operable, supplemental bellows and interengaging parts between the expression bellows and supplemental bellows.

5. In a musical instrument, pneumatic playing actions; a main air chamber; a connection between the playing actions and main air chamber; a valve governing said connection; an expression bellows provided with an opening by which to exhaust said expression bellows; an auxiliary expression bellows controlling an opening to permit sudden expansion of the expression bellows; and means including a spring connecting said valve and said expression bellows.

6. In a musical instrument, pneumatic playing actions; a source of power for op erating said actions, a regulator having avalve between said source of power and said actions; a spring connected to said regulator; and automatically operable means acting upon said spring for varying the force of said spring upon the regulator, either substantially instantaneously to produce steps of change in playing intensity, or gradually to produce crescendo or diminuendo effects.

7. In a musical instrument, automatic playing actions; a source of power for operating said actions; a regulator between said source of power and said actions; yielding transmission means connected to said regulator; and means for varying by dis tinct steps or gradually, the force transmitted to the regulator by said yielding means.

8. In combination striker pneumatics and a main source of power, a regulator for main taining uniformity of pressure of the main source of power upon the striker pneumatics at all degrees of pressure irrespective of the number of striker pneumatics actuated at any one time, a pneumatic having a resilient connection with the regulator for tensioning the latter, a valve mechanism controlling said pneumatic and a connection from said valve mechanism to the pneumatic for maintaining said pneumatic in any desired position 0? adjustment, and automatic devices for varying the position of the connection taining said pneumatic in any, desired poSi: 16

tion of adjustment and automatic pneumatic devices controlled from a tracker-board for varying the. position of the connection and eque n l f he valv a tion and pneumatic device with reference to said 20 valves.

In testimony whereof, I have. signed my name to this specification, in the presence of t o subsc b ngi esses GEAR ES EAS QDD R W tn ss r A, James I. E. EDGAR. 

